/*
** $Id: ldblib.c,v 1.132 2012/01/19 20:14:44 roberto Exp $
** Interface from Lua to its debug API
** See Copyright Notice in lua.h
*/


#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define ldblib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"


#define HOOKKEY		"_HKEY"



static int db_getregistry (lua_State *L) {
	lua_pushvalue(L, LUA_REGISTRYINDEX);
	return 1;
}


static int db_getmetatable (lua_State *L) {
	luaL_checkany(L, 1);
	if (!lua_getmetatable(L, 1)) {
		lua_pushnil(L);  /* no metatable */
	}
	return 1;
}


static int db_setmetatable (lua_State *L) {
	int t = lua_type(L, 2);
	luaL_argcheck(L, t == LUA_TNIL || t == LUA_TTABLE, 2,
		"nil or table expected");
	lua_settop(L, 2);
	lua_setmetatable(L, 1);
	return 1;  /* return 1st argument */
}


static int db_getuservalue (lua_State *L) {
	if (lua_type(L, 1) != LUA_TUSERDATA)
		lua_pushnil(L);
	else
		lua_getuservalue(L, 1);
	return 1;
}


static int db_setuservalue (lua_State *L) {
	if (lua_type(L, 1) == LUA_TLIGHTUSERDATA)
		luaL_argerror(L, 1, "full userdata expected, got light userdata");
	luaL_checktype(L, 1, LUA_TUSERDATA);
	if (!lua_isnoneornil(L, 2))
		luaL_checktype(L, 2, LUA_TTABLE);
	lua_settop(L, 2);
	lua_setuservalue(L, 1);
	return 1;
}


static void settabss (lua_State *L, const char *i, const char *v) {
	lua_pushstring(L, v);
	lua_setfield(L, -2, i);
}


static void settabsi (lua_State *L, const char *i, int v) {
	lua_pushinteger(L, v);
	lua_setfield(L, -2, i);
}


static void settabsb (lua_State *L, const char *i, int v) {
	lua_pushboolean(L, v);
	lua_setfield(L, -2, i);
}


static lua_State *getthread (lua_State *L, int *arg) {
	if (lua_isthread(L, 1)) {
		*arg = 1;
		return lua_tothread(L, 1);
	}
	else {
		*arg = 0;
		return L;
	}
}


static void treatstackoption (lua_State *L, lua_State *L1, const char *fname) {
	if (L == L1) {
		lua_pushvalue(L, -2);
		lua_remove(L, -3);
	}
	else
		lua_xmove(L1, L, 1);
	lua_setfield(L, -2, fname);
}


static int db_getinfo (lua_State *L) {
	lua_Debug ar;
	int arg;
	lua_State *L1 = getthread(L, &arg);
	const char *options = luaL_optstring(L, arg+2, "flnStu");
	if (lua_isnumber(L, arg+1)) {
		if (!lua_getstack(L1, (int)lua_tointeger(L, arg+1), &ar)) {
			lua_pushnil(L);  /* level out of range */
			return 1;
		}
	}
	else if (lua_isfunction(L, arg+1)) {
		lua_pushfstring(L, ">%s", options);
		options = lua_tostring(L, -1);
		lua_pushvalue(L, arg+1);
		lua_xmove(L, L1, 1);
	}
	else
		return luaL_argerror(L, arg+1, "function or level expected");
	if (!lua_getinfo(L1, options, &ar))
		return luaL_argerror(L, arg+2, "invalid option");
	lua_createtable(L, 0, 2);
	if (strchr(options, 'S')) {
		settabss(L, "source", ar.source);
		settabss(L, "short_src", ar.short_src);
		settabsi(L, "linedefined", ar.linedefined);
		settabsi(L, "lastlinedefined", ar.lastlinedefined);
		settabss(L, "what", ar.what);
	}
	if (strchr(options, 'l'))
		settabsi(L, "currentline", ar.currentline);
	if (strchr(options, 'u')) {
		settabsi(L, "nups", ar.nups);
		settabsi(L, "nparams", ar.nparams);
		settabsb(L, "isvararg", ar.isvararg);
	}
	if (strchr(options, 'n')) {
		settabss(L, "name", ar.name);
		settabss(L, "namewhat", ar.namewhat);
	}
	if (strchr(options, 't'))
		settabsb(L, "istailcall", ar.istailcall);
	if (strchr(options, 'L'))
		treatstackoption(L, L1, "activelines");
	if (strchr(options, 'f'))
		treatstackoption(L, L1, "func");
	return 1;  /* return table */
}


static int db_getlocal (lua_State *L) {
	int arg;
	lua_State *L1 = getthread(L, &arg);
	lua_Debug ar;
	const char *name;
	int nvar = luaL_checkint(L, arg+2);  /* local-variable index */
	if (lua_isfunction(L, arg + 1)) {  /* function argument? */
		lua_pushvalue(L, arg + 1);  /* push function */
		lua_pushstring(L, lua_getlocal(L, NULL, nvar));  /* push local name */
		return 1;
	}
	else {  /* stack-level argument */
		if (!lua_getstack(L1, luaL_checkint(L, arg+1), &ar))  /* out of range? */
			return luaL_argerror(L, arg+1, "level out of range");
		name = lua_getlocal(L1, &ar, nvar);
		if (name) {
			lua_xmove(L1, L, 1);  /* push local value */
			lua_pushstring(L, name);  /* push name */
			lua_pushvalue(L, -2);  /* re-order */
			return 2;
		}
		else {
			lua_pushnil(L);  /* no name (nor value) */
			return 1;
		}
	}
}


static int db_setlocal (lua_State *L) {
	int arg;
	lua_State *L1 = getthread(L, &arg);
	lua_Debug ar;
	if (!lua_getstack(L1, luaL_checkint(L, arg+1), &ar))  /* out of range? */
		return luaL_argerror(L, arg+1, "level out of range");
	luaL_checkany(L, arg+3);
	lua_settop(L, arg+3);
	lua_xmove(L, L1, 1);
	lua_pushstring(L, lua_setlocal(L1, &ar, luaL_checkint(L, arg+2)));
	return 1;
}


static int auxupvalue (lua_State *L, int get) {
	const char *name;
	int n = luaL_checkint(L, 2);
	luaL_checktype(L, 1, LUA_TFUNCTION);
	name = get ? lua_getupvalue(L, 1, n) : lua_setupvalue(L, 1, n);
	if (name == NULL) return 0;
	lua_pushstring(L, name);
	lua_insert(L, -(get+1));
	return get + 1;
}


static int db_getupvalue (lua_State *L) {
	return auxupvalue(L, 1);
}


static int db_setupvalue (lua_State *L) {
	luaL_checkany(L, 3);
	return auxupvalue(L, 0);
}


static int checkupval (lua_State *L, int argf, int argnup) {
	lua_Debug ar;
	int nup = luaL_checkint(L, argnup);
	luaL_checktype(L, argf, LUA_TFUNCTION);
	lua_pushvalue(L, argf);
	lua_getinfo(L, ">u", &ar);
	luaL_argcheck(L, 1 <= nup && nup <= ar.nups, argnup, "invalid upvalue index");
	return nup;
}


static int db_upvalueid (lua_State *L) {
	int n = checkupval(L, 1, 2);
	lua_pushlightuserdata(L, lua_upvalueid(L, 1, n));
	return 1;
}


static int db_upvaluejoin (lua_State *L) {
	int n1 = checkupval(L, 1, 2);
	int n2 = checkupval(L, 3, 4);
	luaL_argcheck(L, !lua_iscfunction(L, 1), 1, "Lua function expected");
	luaL_argcheck(L, !lua_iscfunction(L, 3), 3, "Lua function expected");
	lua_upvaluejoin(L, 1, n1, 3, n2);
	return 0;
}


#define gethooktable(L)	luaL_getsubtable(L, LUA_REGISTRYINDEX, HOOKKEY)


static void hookf (lua_State *L, lua_Debug *ar) {
	static const char *const hooknames[] =
	{"call", "return", "line", "count", "tail call"};
	gethooktable(L);
	lua_pushthread(L);
	lua_rawget(L, -2);
	if (lua_isfunction(L, -1)) {
		lua_pushstring(L, hooknames[(int)ar->event]);
		if (ar->currentline >= 0)
			lua_pushinteger(L, ar->currentline);
		else lua_pushnil(L);
		lua_assert(lua_getinfo(L, "lS", ar));
		lua_call(L, 2, 0);
	}
}


static int makemask (const char *smask, int count) {
	int mask = 0;
	if (strchr(smask, 'c')) mask |= LUA_MASKCALL;
	if (strchr(smask, 'r')) mask |= LUA_MASKRET;
	if (strchr(smask, 'l')) mask |= LUA_MASKLINE;
	if (count > 0) mask |= LUA_MASKCOUNT;
	return mask;
}


static char *unmakemask (int mask, char *smask) {
	int i = 0;
	if (mask & LUA_MASKCALL) smask[i++] = 'c';
	if (mask & LUA_MASKRET) smask[i++] = 'r';
	if (mask & LUA_MASKLINE) smask[i++] = 'l';
	smask[i] = '\0';
	return smask;
}


static int db_sethook (lua_State *L) {
	int arg, mask, count;
	lua_Hook func;
	lua_State *L1 = getthread(L, &arg);
	if (lua_isnoneornil(L, arg+1)) {
		lua_settop(L, arg+1);
		func = NULL; mask = 0; count = 0;  /* turn off hooks */
	}
	else {
		const char *smask = luaL_checkstring(L, arg+2);
		luaL_checktype(L, arg+1, LUA_TFUNCTION);
		count = luaL_optint(L, arg+3, 0);
		func = hookf; mask = makemask(smask, count);
	}
	if (gethooktable(L) == 0) {  /* creating hook table? */
		lua_pushstring(L, "k");
		lua_setfield(L, -2, "__mode");  /** hooktable.__mode = "k" */
		lua_pushvalue(L, -1);
		lua_setmetatable(L, -2);  /* setmetatable(hooktable) = hooktable */
	}
	lua_pushthread(L1); lua_xmove(L1, L, 1);
	lua_pushvalue(L, arg+1);
	lua_rawset(L, -3);  /* set new hook */
	lua_sethook(L1, func, mask, count);  /* set hooks */
	return 0;
}


static int db_gethook (lua_State *L) {
	int arg;
	lua_State *L1 = getthread(L, &arg);
	char buff[5];
	int mask = lua_gethookmask(L1);
	lua_Hook hook = lua_gethook(L1);
	if (hook != NULL && hook != hookf)  /* external hook? */
		lua_pushliteral(L, "external hook");
	else {
		gethooktable(L);
		lua_pushthread(L1); lua_xmove(L1, L, 1);
		lua_rawget(L, -2);   /* get hook */
		lua_remove(L, -2);  /* remove hook table */
	}
	lua_pushstring(L, unmakemask(mask, buff));
	lua_pushinteger(L, lua_gethookcount(L1));
	return 3;
}


static int db_debug (lua_State *L) {
	for (;;) {
		char buffer[250];
		luai_writestringerror("%s", "lua_debug> ");
		if (fgets(buffer, sizeof(buffer), stdin) == 0 ||
			strcmp(buffer, "cont\n") == 0)
			return 0;
		if (luaL_loadbuffer(L, buffer, strlen(buffer), "=(debug command)") ||
			lua_pcall(L, 0, 0, 0))
			luai_writestringerror("%s\n", lua_tostring(L, -1));
		lua_settop(L, 0);  /* remove eventual returns */
	}
}


static int db_traceback (lua_State *L) {
	int arg;
	lua_State *L1 = getthread(L, &arg);
	const char *msg = lua_tostring(L, arg + 1);
	if (msg == NULL && !lua_isnoneornil(L, arg + 1))  /* non-string 'msg'? */
		lua_pushvalue(L, arg + 1);  /* return it untouched */
	else {
		int level = luaL_optint(L, arg + 2, (L == L1) ? 1 : 0);
		luaL_traceback(L, L1, msg, level);
	}
	return 1;
}


static const luaL_Reg dblib[] = {
	{"debug", db_debug},
	{"getuservalue", db_getuservalue},
	{"gethook", db_gethook},
	{"getinfo", db_getinfo},
	{"getlocal", db_getlocal},
	{"getregistry", db_getregistry},
	{"getmetatable", db_getmetatable},
	{"getupvalue", db_getupvalue},
	{"upvaluejoin", db_upvaluejoin},
	{"upvalueid", db_upvalueid},
	{"setuservalue", db_setuservalue},
	{"sethook", db_sethook},
	{"setlocal", db_setlocal},
	{"setmetatable", db_setmetatable},
	{"setupvalue", db_setupvalue},
	{"traceback", db_traceback},
	{NULL, NULL}
};


LUAMOD_API int luaopen_debug (lua_State *L) {
	luaL_newlib(L, dblib);
	return 1;
}

